Method

1. Heat butter and cardamom pods in a small saucepan until melted and foaming. Continue cooking over low heat until the solids at the bottom turn a deep brown colour and smell nutty. Strain into a bowl to remove cardamom and cool to room temperature.

2. Blend pistachios and icing sugar in a food processor for approximately 2 minutes until very finely ground (a few chunks are ok).

3. Beat egg whites until soft peaks form and then using a metal spoon, fold in the icing sugar mixture in batches until incorporated. Fold in flour and cooled butter mixture, alternately.

4. Pour mixture into a side and base lined 23cm springform pan. Stud the cake with blackberries and sprinkle with extra pistachios. Bake at 160°C for 1 hour and 25 minutes, until the centre of the torte is just set and skewer comes out clean when tested. Cool in pan for 15 minutes before transferring to a wire rack to cool to room temperature. Serve with double cream.